Mobile devices with various methods of connectivity are now for many people becoming the primary gateway to the internet and also a major storage point for personal information. This is in addition to the normal range of personal computers and furthermore sensor devices plus internet based providers. Combining these devices together and lately the applications and the information stored by those applications is a major challenge of interoperability. This is achieved through numerous, individual and personal spaces in which persons, groups of persons, etc. can place, share, interact and manipulate webs of information with their own locally agreed semantics without necessarily conforming to an unobtainable, global whole. These information spaces, often referred to as smart spaces, are projections of the ‘Giant Global Graph’ in which one can apply semantics and reasoning at a local level.
Each smart space entity can be considered as an aggregated information set from different sources. This multi-sourcing consideration is very flexible since it accounts that the same piece of information can come from different sources. Information is represented using Semantic Web standards such as Resource Description Framework (RDF), RDF Schema (RDFS), OWL (Web Ontology Language), FOAF (Friend of a Friend ontology), rule sets in RuleML (Rule Markup Language), etc.
In an information space, information requested by a user may be distributed over several information sets and therefore in order to deduce an accurate answer to a request there is the need for combining (merging) the information from different sources into a smart space. Furthermore, due to several reasons such as security issues, changing agreements and so on, it could be necessary for an information space to be split into two or more smaller spaces. The process of splitting one space may be volatile, meaning that merging the split spaces together again may not produce the initial space, since some links between information could be lost. Conventionally, there is no strict order to justify “split-merge” or “merge-split” procedures. The process involves high volatility in terms of which split spaces can be merged and which solid spaces (merged earlier) can be split without damaging the initial contents.